fix overflow in matrixproc, and add debugging code to test that
git-svn-id: http://skia.googlecode.com/svn/trunk@548 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkBitmapProcShader.cpp b/src/core/SkBitmapProcShader.cpp
index bd4fece..c3fd7d0 100644
--- a/src/core/SkBitmapProcShader.cpp
+++ b/src/core/SkBitmapProcShader.cpp
@@ -137,6 +137,15 @@
#define BUF_MAX 128
+#define TEST_BUFFER_OVERRITEx
+
+#ifdef TEST_BUFFER_OVERRITE
+ #define TEST_BUFFER_EXTRA 32
+ #define TEST_PATTERN 0x88888888
+#else
+ #define TEST_BUFFER_EXTRA 0
+#endif
+
void SkBitmapProcShader::shadeSpan(int x, int y, SkPMColor dstC[], int count) {
const SkBitmapProcState& state = fState;
if (state.fShaderProc32) {
@@ -144,10 +153,10 @@
return;
}
- uint32_t buffer[BUF_MAX];
+ uint32_t buffer[BUF_MAX + TEST_BUFFER_EXTRA];
SkBitmapProcState::MatrixProc mproc = state.fMatrixProc;
SkBitmapProcState::SampleProc32 sproc = state.fSampleProc32;
- int max = fState.maxCountForBufferSize(sizeof(buffer));
+ int max = fState.maxCountForBufferSize(sizeof(buffer[0]) * BUF_MAX);
SkASSERT(state.fBitmap->getPixels());
SkASSERT(state.fBitmap->pixelRef() == NULL ||
@@ -158,12 +167,24 @@
if (n > max) {
n = max;
}
+ SkASSERT(n > 0 && n < BUF_MAX*2);
+#ifdef TEST_BUFFER_OVERRITE
+ for (int i = 0; i < TEST_BUFFER_EXTRA; i++) {
+ buffer[BUF_MAX + i] = TEST_PATTERN;
+ }
+#endif
mproc(state, buffer, n, x, y);
+#ifdef TEST_BUFFER_OVERRITE
+ for (int j = 0; j < TEST_BUFFER_EXTRA; j++) {
+ SkASSERT(buffer[BUF_MAX + j] == TEST_PATTERN);
+ }
+#endif
sproc(state, buffer, n, dstC);
if ((count -= n) == 0) {
break;
}
+ SkASSERT(count > 0);
x += n;
dstC += n;
}
diff --git a/src/core/SkBitmapProcState.cpp b/src/core/SkBitmapProcState.cpp
index eabd966..e54818d 100644
--- a/src/core/SkBitmapProcState.cpp
+++ b/src/core/SkBitmapProcState.cpp
@@ -543,7 +543,6 @@
*/
int SkBitmapProcState::maxCountForBufferSize(size_t bufferSize) const {
int32_t size = static_cast<int32_t>(bufferSize);
- int perElemShift;
size &= ~3; // only care about 4-byte aligned chunks
if (fInvType <= (SkMatrix::kTranslate_Mask | SkMatrix::kScale_Mask)) {
@@ -551,11 +550,15 @@
if (size < 0) {
size = 0;
}
- perElemShift = fDoFilter ? 2 : 1;
+ size >>= 1;
} else {
- perElemShift = fDoFilter ? 3 : 2;
+ size >>= 2;
}
- return size >> perElemShift;
+ if (fDoFilter) {
+ size >>= 1;
+ }
+
+ return size;
}
diff --git a/src/core/SkBitmapProcState.h b/src/core/SkBitmapProcState.h
index dd73c33..303696f 100644
--- a/src/core/SkBitmapProcState.h
+++ b/src/core/SkBitmapProcState.h
@@ -91,10 +91,11 @@
*/
void platformProcs();
- /** Given the size of a buffer, to be used for calling the matrix and
- sample procs, this return the maximum count that can be stored in the
- buffer, taking into account that filtering and scale-vs-affine affect
- this value.
+ /** Given the byte size of the index buffer to be passed to the matrix proc,
+ return the maximum number of resulting pixels that can be computed
+ (i.e. the number of SkPMColor values to be written by the sample proc).
+ This routine takes into account that filtering and scale-vs-affine
+ affect the amount of buffer space needed.
Only valid to call after chooseProcs (setContext) has been called. It is
safe to call this inside the shader's shadeSpan() method.
diff --git a/src/core/SkBitmapProcState_matrixProcs.cpp b/src/core/SkBitmapProcState_matrixProcs.cpp
index 6654312..d0bc8d8 100644
--- a/src/core/SkBitmapProcState_matrixProcs.cpp
+++ b/src/core/SkBitmapProcState_matrixProcs.cpp
@@ -368,7 +368,7 @@
}
// fill the remaining with the max value
- sk_memset16(xptr, width - 1, count * sizeof(uint16_t));
+ sk_memset16(xptr, width - 1, count);
}
static void repeatx_nofilter_trans(const SkBitmapProcState& s,